Refrigerant flow has a significant impact on evaporator coil performance. Adequate refrigerant flow is necessary to ensure that the evaporator coil can absorb heat from the indoor air effectively. If the refrigerant flow is restricted or insufficient, the evaporator coil may not be able to absorb heat properly, leading to reduced cooling capacity, increased energy consumption, and potential coil freezing. On the other hand, excessive refrigerant flow can also lead to inefficient operation, as it can cause the coil to become over-cooled, resulting in wasted energy.